So, you say it's been awhile since you've gotten a good look at a purple wartyback mussel or a short-eared owl?

Well, there's a good reason for that, as it turns out. Both are on the list of 483 endangered species in Illinois. You're in luck, though, since both also happen to be included in nature photographer Carol Freeman's exhibit "Endangered Beauty" opening April 23 in Brushwood Center at Ryerson Woods in Deerfield.

"Most nature photographers have a specialty and no one was doing endangered species, so I thought, 'Why not me?,'" said Glenview resident Freeman, who had already begun, unofficially, while documenting threatened species for the Illinois Nature Conservancy and Chicago Wilderness magazine.

Graphic design was Freeman's first professional choice back in 1990. She had always loved photography, however, so much so that she sought out clients that required photo work as well.

At the time, she was most interested in shooting outdoor sports along the lines of ballooning, windsurfing and sailing. That all changed, however, when the clients who owned Evanston's Upstart Crow, turned her on to bird watching.

Freeman eventually got out of the graphic design business and devoted herself to nature photography full-time. In 2003, she decided to take on the challenge of photographing all the endangered species in Illinois.

Which turned out to be much more challenging than she had imagined. Roughly 14 years later, Freeman has shot 160 species on the list, only about a third of the list, despite dedicated, expert help from conservation groups like Plants of Concern.

Of course, it's easy enough to understand why it's taking so long. The fact that a species has become endangered essentially means there aren't as many of them out there to be found.

Consider Freeman's greatest challenge to date — and her greatest coup — the Hine's Emerald Dragonfly. The Hines is so extremely endangered, in fact, that it's made it onto the federal endangered species list as well. Illinois is the one of the few places in the country it can be found. Especially one small, isolated spot in the woods about an hour's drive from Freeman's home. Freeman made the drive whenever she could, however, on weekends for three long years. And saw nothing. Until one day, one of them landed on a cattail off the trail and she was able to inch over and take all the shots she needed to verify it.

"That was really gratifying," she said. "A great feeling."

Meanwhile, Freeman continues with her mission, occasionally encouraged when some species, such as the Peregrine Falcon are de-listed. And by the great diversity of animal and plant life still extant in the state — even if they are severely threatened.

"It's amazing how many species are barely clinging to existence in this state, from tiny, quarter-inch leaf hoppers to six-foot sandhill cranes and trees and fish and snails and mussels and wolves," she said. "I don't think people are aware of how much is at risk. I always encourage people to get outside and appreciate nature whenever they have the chance, because you never know when a species might become endangered."